by February 28, 2004 0 comments



This PCQLinux distribution has extensive options for video encoding, editing and playing. These are facilitated in the full install and Multimedia Workstation install using Cinelerra, LiVES and Blender for editing and mplayer and Noatun for playing. While LiVES is a basic video editor, Cinelerra is what gives the cutting edge stuff to you, using its clustering function. Blender, on the other hand, is more of a compositing solution in addition to being a 3D modeling and animation solution. 

On the playing front, while Noatun is available in the KDE 3.2 environment, mplayer and gmplayer are available in Gnome. The real media codec of mplayer is also installed to enable real media file playing.

Video encoding
For encoding video from one format to another you can use mencoder, which is included in PCQLinux 2004. It can decode from all mplayer playable formats to other mplayer playable formats. It plays most MPEG/VOB, AVI, ASF/WMA/WMV, RM, QT/ MOV/MP4, OGG/OGM, VIVO, FLI, NuppelVideo, yuv4mpeg, FILM and RoQ files, supported by many native, XAnim, and Win32 DLL codecs. These can be converted into DivX, XviD, etc. It is a command-line based tool and uses the following syntax for execution.

#mencoder [options] [ file | URL | – ] [-o file]
For example, if you want to convert voice.mpg to voice.avi, then, 

#mencoder voice.mpg voice.avi

Video editing
This version comes bundled with a video-editing suite called Cinelerra. It is one of the most extensible video editors available on the Linux platform. We will use the same.

Open a video, add effects to it and render it on multiple machines using the render farm function available in Cinelerra. Open the terminal window and type Cinelerra to invoke the Cinelerra video editor. On the first look it may look like an amateurish video-editor, but under its frog skin lies a prince. It would pleasantly surprise you with its plethora of features and an easy learning curve. 

For a sample exercise we would make a new file, add an effect to it and subsequently render it. In the end we would discuss how you can use the Cinelerra render farm to render the videos over a cluster on a network. 

When you open the software, there would be an empty project open for you. Import a file using the ‘Load Files…’ command in the File menu. Make sure that you select ‘Make new resources only…’ in the Load File dialog. This will make sure that the files that are being imported are added to the library and are not replacing any resources. Once added, you can drag them onto the viewer window and play them using the play button of that window. You can now edit the video using the self-explanatory buttons in the time line. You would use the ‘[‘ and’]’ button to select a part of the video and ‘v’ key to add it to the composition.

With the editing out of the way you can add any audio to the composition by importing it to the library and dragging it on the timeline.

Similarly, you can add effects to the composition by using the effects library in the software. The effects and transitions can be found as folders in the resources window. Choose ‘Show Resources’ from the Window menu to see the resources window if it not already visible. There are two separate folders for effects and transitions. These can be simply dragged on the timeline or the compositor window to be previewed and applied real time.

Adding new users from the gui
To create a new user account, log in as a root from the KDE 3.2 desktop. Then click on start button ‘K’ and click Lost and Found>Users and Groups. This will open a Users manager program.
Here you can add/remove or modify user properties. Click on the Add User button. This will bring a small window, where you need to give the new user name and its password. After creating a new user account, logout from the root and re-login in KDE 3.2 from the new user account.

Finally, you can render the movie in the format desired using the render option in the file menu. If your file is too big and you need more than one machine to render the video, you can use the above mentioned render farm capabilities of Cinelerra. 
To create the NFS share, fire up your Web browser and open Webmin and enter 127.0.0.1:10000. Then go to the networking icon, click on ‘NFS Exports’ and then on ‘Add a new export’ hyperlink. A form will open up, on which fill the ‘Directory to Export’ field with a folder in your machine having full rights. Let it be /render. Be sure the ‘Export to’ option is selected as ‘Everyone’, ‘Asscee mode’ is in Read/Write mode and ‘Trust remote users’ is in ‘Everyone mode’. Now create the share by clicking on the ‘Create’ button. Finally, restart nfs by issuing the following command

#/etc/init.d/nfs restart

Now you have to mount the NFS share to each machine in your network to the same location. You can do that by running the ‘mount’ command from the command line of the client node. The command should look something like this:

#mount -t nfs <IP of the NFS/Cinelerra Server>:/shareddirectory /shareddirectory

For example, let’s suppose the Cinelerra/NFS server’s IP address is 10.10.10.1 and the NFS shared folder is /render. So, you have to run the following command in each node machine.

#mount -t nfs 10.10.10.1:/render /render

The master node is the front end for the user and runs the GUI. On the other hand, you would need to run the following command on the nodes to connect to the master node.

#Cinelerra [-d] [port number]
eg. Cinelerra —d 400

This will start Cinelerra in command prompt mode and make it listen to port 400 for commands from the master node for rendering.

Playing video
You can play video using many players in the distribution, including NoAtun, mPlayer, gmplayer etc. We would give an example of using gmplayer for the same. Open gmmplayer from the command line using the following commands

#gmplayer

This would open a GUI-based player. You can use the various controls buttons such as eject, play and forward to play your favorite files.

Geetaj Channana

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